...and rules until his death on May 25, 1992.
So he becomes General Secretary of the CPSU in March, Chairman of the Presidium of the Supreme Soviet on 27 July. He sends Kuznetsov to retirement in 1986 and chooses Pyotr Demichev (1918-2010), his old Moscow party apparatus ally as the new First Deputy Chairman of the Supreme Soviet, and makes Ivan Kapitonov (1915-2002) the second secretary of the central committee.
The 28th party congress is held in 1991.
What kind of policies would Grishin pursue and would his election preserve the USSR? For the little I've been able to find about his policies in English it seems he was a conservative, but still somewhat efficient and active as Moscow party boss. He lost a power struggle to Andropov in 1982, so he might not follow Andropov's policies.
If Kapitonov succeeds him upon his death as the General Secretary, would he be pushed to retire in the 1996 party congress? Does anyone know or have a good guess whether in the Soviet Union the Brezhnevite leaders would have continued in office until death, serving in their posts in their 90s, Mugabe style, or would they have retired at around 80?